Viking #VGCC530-4B (propane) Oven/Broiler dead, all other features (conv. fan, light, burners) operational

[Andy Douglass]

This range is over 10 years old but I don't want to send it to the graveyard. Originally gas, but I converted it to propane 2 years ago. In the middle of roasting onions at 250 degrees yesterday, oven burner stopped working. Broiler would not ignite either. Convection fan, oven light, and all four burners work fine.

I have tested that Oven Control is receiving 120v (Step 1 in service manual troubleshooting). 

Step 2 reads:

"Check oven control board with oven control OFF    0.5 VAC present H2 to S1?"

Per the wiring diagram in the service manual, "Burner 2 Input H2" is a pin on on the Direct Spark Module, which is connected to "BA" on the Oven Control by a blue wire. "Valve 2 Drive S1" is a pin on the Direct Spark Module which is connected to the Bake Solenoid by a brown wire.

My question: To complete Step 2 (0.5 VAC present H2 to S1), how do I test with my multimeter? The lowest AC voltage setting on my multimeter is 200, not sure if that will be accurate enough to test for .5v. Also, I understand testing for 120v to the oven control since it means connecting one lead to the hot and one to the neutral. But testing H2 to S1 seems like I am only testing the hot on either side of the spark module. Do I connect red lead from multimeter to H2 and black lead to S1?

Thanks for any help,

Andy

[Nathaniel Peterson]

On 2/21/2024 at 3:19 PM, Andy Douglass said:

This range is over 10 years old but I don't want to send it to the graveyard. Originally gas, but I converted it to propane 2 years ago. In the middle of roasting onions at 250 degrees yesterday, oven burner stopped working. Broiler would not ignite either. Convection fan, oven light, and all four burners work fine.

I have tested that Oven Control is receiving 120v (Step 1 in service manual troubleshooting). 

Step 2 reads:

"Check oven control board with oven control OFF    0.5 VAC present H2 to S1?"

Per the wiring diagram in the service manual, "Burner 2 Input H2" is a pin on on the Direct Spark Module, which is connected to "BA" on the Oven Control by a blue wire. "Valve 2 Drive S1" is a pin on the Direct Spark Module which is connected to the Bake Solenoid by a brown wire.

My question: To complete Step 2 (0.5 VAC present H2 to S1), how do I test with my multimeter? The lowest AC voltage setting on my multimeter is 200, not sure if that will be accurate enough to test for .5v. Also, I understand testing for 120v to the oven control since it means connecting one lead to the hot and one to the neutral. But testing H2 to S1 seems like I am only testing the hot on either side of the spark module. Do I connect red lead from multimeter to H2 and black lead to S1?

Thanks for any help,

Andy

It's going to be 5 volts. Nothing will run on .5 v IMO. At least I haven't seen it in 20 years. Another thing when looking at the diagram look to see what's common that both bake and broil functions share. Show us a picture of the wiring diagram in it's entirety so we can help you figure it out.

[Nathaniel Peterson]

21 minutes ago, Nathaniel Peterson said:

It's going to be 5 volts. Nothing will run on .5 v IMO. At least I haven't seen it in 20 years. Another thing when looking at the diagram look to see what's common that both bake and broil functions share. Show us a picture of the wiring diagram in it's entirety so we can help you figure it out.

5 volts dc. When testing dc voltage you'll just get a negative voltage reading if you're meter probes are on backwards. Just disregard and assume it's positive or reverse your meter leads. Unless you have a really good meter with protection make sure you set your meter to a/c for the high voltage 120 volts and d/c for the 5 vdc. Proceed as long as you assume all responsibility if you make a mistake. Safety Darren alert lol

[Andy Douglass]

Thanks for the quick replies. I'm attaching a screen shot of the wiring diagram and a screenshot of the service manual troubleshooting page I referenced earlier. Third attachment is the component characteristics page of the same manual.

As seen on items #2 and #3 on the third attachment, the spark module is supposed to receive 120v from the oven control when it is set to Bake (BA -> blue wire -> H2) and when it is set to Broil (BR -> violet wire -> H1). After my first post, I verified that when oven control is set to Bake, 120v at point BA, and when set to Broil, 120v to BR.

The second step of troubleshooting is what has me stumped, as it asks to verify 0.5 VAC from H2 to S1 while the oven control is set off, and if this is not present, to replace the oven control. If it passes that test, then third test is to verify that 7.54v H2 to S1 with oven set to Bake and igniter arcing, and if fail, replace oven control.  H2 and S1 are both points on the spark module, so how would a failure between them indicate a problem with the oven control? If the oven control is supposed to send 7.54v when set to bake (350 degrees), why not just test at point BA on the oven control?

I don't know enough about how this stuff works, but based on the info in the three attachments, it looks to me like the oven control is supposed to send 120VAC to the spark module on either the bake or broil wire when it is set to bake or broil and the RTD confirms temp is low enough to fire either burner. Then again, the spark module has its own 120v power, so that doesn't make sense either. If I get past what I see as a logic failure with the troubleshooting tests, how do I use a multimeter to safely test for 7.54VAC H2 to S1 when the oven control is set to bake and is sending 120v to H2, and it appears S1 is supposed to send 7.54VAC to the bake solenoid?

Thanks again for the help!

 

[Andy Douglass]

PS: I also verified +/- 1050 ohms at the RTD connection on the oven control, so it appears RTD is good.

[Nathaniel Peterson]

18 hours ago, Andy Douglass said:

Thanks for the quick replies. I'm attaching a screen shot of the wiring diagram and a screenshot of the service manual troubleshooting page I referenced earlier. Third attachment is the component characteristics page of the same manual.

As seen on items #2 and #3 on the third attachment, the spark module is supposed to receive 120v from the oven control when it is set to Bake (BA -> blue wire -> H2) and when it is set to Broil (BR -> violet wire -> H1). After my first post, I verified that when oven control is set to Bake, 120v at point BA, and when set to Broil, 120v to BR.

The second step of troubleshooting is what has me stumped, as it asks to verify 0.5 VAC from H2 to S1 while the oven control is set off, and if this is not present, to replace the oven control. If it passes that test, then third test is to verify that 7.54v H2 to S1 with oven set to Bake and igniter arcing, and if fail, replace oven control.  H2 and S1 are both points on the spark module, so how would a failure between them indicate a problem with the oven control? If the oven control is supposed to send 7.54v when set to bake (350 degrees), why not just test at point BA on the oven control?

I don't know enough about how this stuff works, but based on the info in the three attachments, it looks to me like the oven control is supposed to send 120VAC to the spark module on either the bake or broil wire when it is set to bake or broil and the RTD confirms temp is low enough to fire either burner. Then again, the spark module has its own 120v power, so that doesn't make sense either. If I get past what I see as a logic failure with the troubleshooting tests, how do I use a multimeter to safely test for 7.54VAC H2 to S1 when the oven control is set to bake and is sending 120v to H2, and it appears S1 is supposed to send 7.54VAC to the bake solenoid?

Thanks again for the help!

 

The manual I have states 5 volts dc at the thermostat for the electronic thermostat selector knob. Yes according to the sheet you provided it means bad oven control if not getting 7.54 ish volts on s1-h2. Should be enough room to pull out the oven control to test whatever you need. Just turn off power and pull it out to a safe spot and you may need needle probes for your meter to test unless your leads are small enough to back probe into the connector. I wouldn't try putting your leads in the side of the connector that connects to the pins so you don't spread them out causing new issues.

[Nathaniel Peterson]

Just now, Nathaniel Peterson said:

The manual I have states 5 volts dc at the thermostat for the electronic thermostat selector knob. Yes according to the sheet you provided it means bad oven control if not getting 7.54 ish volts on s1-h2. Should be enough room to pull out the oven control to test whatever you need. Just turn off power and pull it out to a safe spot and you may need needle probes for your meter to test unless your leads are small enough to back probe into the connector. I wouldn't try putting your leads in the side of the connector that connects to the pins so you don't spread them out causing new issues.

The manual I have is for an electric oven and gas cooktop stove. 

[Andy Douglass]

Thanks for the ongoing help. 

This unit is all gas. What I'm having trouble understanding is why a problem between S1-H2 means the oven control is bad? S1 and H2 are both on the spark module. How does testing two points on the spark module tell me anything about the oven control? Why wouldn't I just test the point on the oven control?

Troubleshooting says to test S1-H2 with bake selected and verify 7.54 VAC. But when bake is selected, H2 will have 120VAC (see third attachment). So if I test S1-H2 with bake selected, I am putting one lead on something that is supposed to have 120VAC and putting the other lead to S1 which goes to a solenoid and get a reading of 7.54 VAC. I'm guessing the solenoid is not designed to take 120 VAC, so isn't it dangerous to effectively bridge 120VAC to S1 with the multimeter?

 

 

 

[Nathaniel Peterson]

3 hours ago, Andy Douglass said:

Thanks for the ongoing help. 

This unit is all gas. What I'm having trouble understanding is why a problem between S1-H2 means the oven control is bad? S1 and H2 are both on the spark module. How does testing two points on the spark module tell me anything about the oven control? Why wouldn't I just test the point on the oven control?

Troubleshooting says to test S1-H2 with bake selected and verify 7.54 VAC. But when bake is selected, H2 will have 120VAC (see third attachment). So if I test S1-H2 with bake selected, I am putting one lead on something that is supposed to have 120VAC and putting the other lead to S1 which goes to a solenoid and get a reading of 7.54 VAC. I'm guessing the solenoid is not designed to take 120 VAC, so isn't it dangerous to effectively bridge 120VAC to S1 with the multimeter?

 

 

 

It's confusing to me too. But according to what you posted s1 says neutral and h2 bake solenoid is 10.5 volts. According to the testing procedure it should be fine.

[Andy Douglass]

Could you describe how to test it with my multimeter (what should it be set for) and which point to contact with red lead, which point to contact with black lead, etc. I understand that anything I do based on advice I receive here is my responsibility and there are no guarantees that the advice won't result in damage.

 

Thanks

 

[Nathaniel Peterson]

6 hours ago, Andy Douglass said:

Could you describe how to test it with my multimeter (what should it be set for) and which point to contact with red lead, which point to contact with black lead, etc. I understand that anything I do based on advice I receive here is my responsibility and there are no guarantees that the advice won't result in damage.

 

Thanks

 

If it is true that it's a/c voltage it doesn't matter which probe goes on what lead as long as you're testing the correct points. I'm assuming the the one test point is on the thermostat knob in which you'll need to buy some needle probes or use your wifes sewing needle to fit into the connector. It's pretty much up to you to figure out how to position everything to test while being safe not to arch any components. Set your meter to a/c voltage and make sure the value listed on your meter maximum voltage is great than what you're testing but the lowest voltage it's testing for. Example: most meters will have a 200 max a/c setting or a 400 max a/c setting. Since you're only expecting 10.5 volts a/c put it on the 200 volts a/c setting.

[Andy Douglass]

Thank you. Both test points H2 and S1 are points in the same harness on the spark module, not the oven control/therm, and I can easily test them. Again, it doesn't make sense to me that this test would point to the oven control being faulty when both points in the test are not on the oven control.

Not sure I will actually do it since I already know that H2 will be at 120v based on my earlier test of H2 to N with control set to bake. Also, I don't see anywhere that S1 is indicated as neutral. To me it looks like S1 is supposed to carry 7.54v to the bake solenoid (per the wire diagram S1 goes to the bake solenoid, S2 goes to the broil solenoid, and SC is the common to both), which I believe would indicate SC is neutral. So, still confused why testing from a point known to be 120v (H2) to a point that is supposed to be at 7.54v (S1) is advisable. The only thing I can think of is that the service manual I am looking at is incorrect, and dangerously so.

[Nathaniel Peterson]

2 hours ago, Andy Douglass said:

Thank you. Both test points H2 and S1 are points in the same harness on the spark module, not the oven control/therm, and I can easily test them. Again, it doesn't make sense to me that this test would point to the oven control being faulty when both points in the test are not on the oven control.

Not sure I will actually do it since I already know that H2 will be at 120v based on my earlier test of H2 to N with control set to bake. Also, I don't see anywhere that S1 is indicated as neutral. To me it looks like S1 is supposed to carry 7.54v to the bake solenoid (per the wire diagram S1 goes to the bake solenoid, S2 goes to the broil solenoid, and SC is the common to both), which I believe would indicate SC is neutral. So, still confused why testing from a point known to be 120v (H2) to a point that is supposed to be at 7.54v (S1) is advisable. The only thing I can think of is that the service manual I am looking at is incorrect, and dangerously so.

I also think something is wrong with your service manual. The service manual for the dual fuel model says dc volts on thermostat knob and usually manufacturers don't change stuff like that but who knows I'm just a technician. Maybe there's a good reason they're not using d/c voltage on the all gas model 

[Andy Douglass]

Thanks again for your time. I will try to update this post with any results. I am thinking of paying for a local technician to diagnose for me.

[Nathaniel Peterson]

4 hours ago, Andy Douglass said:

Thanks again for your time. I will try to update this post with any results. I am thinking of paying for a local technician to diagnose for me.

I would ask if they're an authorized Viking technician before you book an appointment for service.